diff options
| author | Heng Qi <hengqi@linux.alibaba.com> | 2023-01-14 16:22:21 +0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2023-01-16 11:15:48 +0000 |
| commit | e814b958ad8857d6f7354d3a189776eb604d86dd (patch) | |
| tree | 8afc498d8dc58a9419f0a9e7cb0adf4e2a2580f6 /drivers/net/virtio_net.c | |
| parent | 484beac2ffc1d1dde5fde601deb28f3a82ac250e (diff) | |
virtio-net: fix calculation of MTU for single-buffer xdp
When single-buffer xdp is loaded, the size of the buffer filled each time
is 'sz = (PAGE_SIZE - headroom - tailroom)', which is the maximum packet
length that the driver allows the device to pass in. Otherwise, the packet
with a length greater than sz will come in, so num_buf will be greater than
or equal to 2, and xdp_linearize_page() will be performed and the packet
will be dropped because the total length is greater than PAGE_SIZE. So the
maximum value of MTU for single-buffer xdp is 'max_sz = sz - ETH_HLEN'.
Signed-off-by: Heng Qi <hengqi@linux.alibaba.com>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/virtio_net.c')
| -rw-r--r-- | drivers/net/virtio_net.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index a3271d2c7c02..81d92978cc92 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -3081,7 +3081,9 @@ static int virtnet_restore_guest_offloads(struct virtnet_info *vi) static int virtnet_xdp_set(struct net_device *dev, struct bpf_prog *prog, struct netlink_ext_ack *extack) { - unsigned long int max_sz = PAGE_SIZE - sizeof(struct padded_vnet_hdr); + unsigned int room = SKB_DATA_ALIGN(VIRTIO_XDP_HEADROOM + + sizeof(struct skb_shared_info)); + unsigned int max_sz = PAGE_SIZE - room - ETH_HLEN; struct virtnet_info *vi = netdev_priv(dev); struct bpf_prog *old_prog; u16 xdp_qp = 0, curr_qp; @@ -3106,7 +3108,7 @@ static int virtnet_xdp_set(struct net_device *dev, struct bpf_prog *prog, if (dev->mtu > max_sz) { NL_SET_ERR_MSG_MOD(extack, "MTU too large to enable XDP"); - netdev_warn(dev, "XDP requires MTU less than %lu\n", max_sz); + netdev_warn(dev, "XDP requires MTU less than %u\n", max_sz); return -EINVAL; } |